Evaluation of Short Stature with Hirsutism in a 16-Year-Old Male
This clinical presentation of short stature with preserved secondary sexual characteristics (hairy legs) in a 16-year-old boy most likely represents constitutional delay of growth and puberty or familial short stature rather than an endocrine disorder, as true endocrine causes would typically suppress pubertal development. 1, 2
Key Diagnostic Distinction
The presence of hairy legs indicates normal androgen production and pubertal progression, which effectively rules out most significant endocrine causes of short stature 3, 1. True endocrine disorders causing short stature—such as growth hormone deficiency, hypothyroidism, or hypopituitarism—would typically present with delayed or absent puberty, not normal secondary sexual characteristics 3, 2.
Most Likely Diagnoses
Constitutional Delay of Growth and Puberty
- Characterized by normal growth velocity (4-7 cm/year during childhood), delayed bone age, and delayed but eventually normal puberty 1, 2
- Final adult height typically falls within normal range 1
- This is a non-pathologic variant and the most common cause of short stature in adolescent males 4
Familial Short Stature
- Presents with early deceleration in linear growth but normal growth velocity thereafter 1, 2
- Normal bone age and normal pubertal development 1, 2
- Final height appropriate for genetic target based on parental heights 2
Essential Diagnostic Workup
Initial Assessment
- Document precise height measurements and calculate height velocity over at least 6 months 2
- Calculate genetic target height using parental heights: [(father's height + mother's height + 13 cm) ÷ 2] 2
- Obtain bone age via left wrist radiograph—this is the critical discriminator between constitutional delay (delayed bone age) and familial short stature (normal bone age) 1, 2
- Review birth measurements to exclude intrauterine growth restriction 1, 2
Physical Examination Specifics
- Assess body proportions (sitting height/standing height ratio) to distinguish proportionate from disproportionate short stature 3, 1
- Document Tanner staging to confirm pubertal progression matches the presence of leg hair 3
- Examine for dysmorphic features or skeletal abnormalities (Madelung deformity, mesomelia) that might suggest SHOX gene mutations 3, 1
Laboratory Evaluation
- IGF-1 level to screen for growth hormone deficiency—should be normal in constitutional delay or familial short stature 2, 5
- Thyroid function tests (TSH, free T4) to exclude hypothyroidism 2
- Complete blood count and comprehensive metabolic panel to exclude chronic systemic disease 2
When to Suspect Pathologic Causes
Red Flags Requiring Further Investigation
- Severely low IGF-1 (more than 2 standard deviations below normal) suggests growth hormone deficiency 2, 5
- Crossing multiple centile lines between ages 3 years and adolescence indicates pathologic growth failure 2
- Growth velocity <4 cm/year during childhood is abnormal and warrants endocrine evaluation 4
- Disproportionate short stature requires skeletal survey to evaluate for skeletal dysplasia 3, 1
Specific Genetic Considerations
- SHOX gene testing should be considered if there are subtle skeletal changes or familial short stature, as skeletal changes may not be apparent until pubertal age and are less commonly noted in males 3, 1
- Chromosomal analysis is not indicated in males with normal pubertal development unless dysmorphic features are present 3, 1
Critical Pitfall to Avoid
The most common error is failing to distinguish between normal variants (constitutional delay, familial short stature) and pathologic causes 1, 2. The presence of normal secondary sexual characteristics (hairy legs) in this 16-year-old boy strongly suggests a normal variant rather than endocrine pathology, as endocrine causes of short stature typically present with delayed bone age AND delayed puberty together 3, 2, 4.
Management Algorithm
If bone age is delayed by 2+ years AND puberty is progressing normally: Diagnosis is constitutional delay—reassure family, monitor growth velocity, consider low-dose testosterone if psychosocial distress is significant 6
If bone age is normal AND growth velocity is normal: Diagnosis is familial short stature—reassure family that final height will match genetic potential, no treatment indicated 1, 2
If IGF-1 is severely low with delayed bone age: This would be inconsistent with normal leg hair development, but if present, requires growth hormone stimulation testing 2, 5
If skeletal abnormalities are present: Obtain skeletal survey and consider SHOX gene testing 3, 1